Continuous flow jet mixer

ABSTRACT

A continuous flow jet mixer includes a tank into which liquid is constantly supplied tangentially, to flow annularly about a concentric inverted overflow cone. The circulating liquid rises to overflow the edge of the cone and flows downward and inward over it as a liquid film. A smaller upright cone spreader rotates therein on a central shaft. Particles of a material such as powder, introduced centrally downward onto the spreader, are centrifugally swirled onto and quickly dissolved in the descending liquid film. Supplemental centrifugal mixing is effected beneath the inverted overflow cone by a mixing disc, rotated on the same central shaft.

United States Patent [191 Iwako Mar. 18, 1975 CONTINUOUS FLOW JET MIXER[75] Inventor: I I i royuki1wako,Tokyo,Japan Related US. ApplicationData [63] Continuation of Ser. No. 262,743, June 14, 1972,

abandoned.

[30] Foreign Application Priority Data July 24, 1971 Japan 46-54935 [56]References Cited UNITED STATES PATENTS 821,790 5/1906 Dorweiler 259/652,102,548 l2/l937 Stratford 259/8 X 3,029,069 4/1962 Cummings 259/43,599,938 8/l97l Anders.....' 259/7 FOREIGN PATENTS OR APPLICATIONS677,401 1/1964 Canada Primary Examiner-Peter Feldman AssistantExaminer-Alan Cantor Attorney, Agent, or Firm-Cooper, Dunham, Clark,Griffin & Moran [57] ABSTRACT A continuous flow jet mixer includes atank into which liquid is constantly supplied tangentially, to flowannularly about a concentric inverted] overflow cone. The circulatingliquid rises to overflow the edge of the cone and flows downward andinward over it as a liquid film. A smaller upright cone spreader rotatestherein on a central shaft. Particles of a material such as powder,introduced centrally downward onto the spreader, are centrifugallyswirled onto and quickly dissolved in the descending liquid film.Supplemental centrifugal mixing is effected beneath the invertedoverflow cone by a mixing disc, rotated on the same central shaft.

17 Claims, 1 Drawing Figure BACKGROUND OF THE INVENTION This inventionrelates to a continuous flow jet mixer wherein liquid is mixed with adownward jet of powder or other liquid, or both, continuously and evenlyat a controlled rate of production.

It has heretofore been difficult to intermix certain materials, forexample, powders, evenly in liquids, with the constant accuracy requiredfor industrial and commercial uses. Irrespective whether batch orcontinuous mix was used, it has been difflcultto effect distribution ofthe material to be intermixed with the liquid with sufficient control asto avoid lumps of powder and other undesirable results.

SUMMARY OF THE INVENTION This invention has for its object the provisionof a mixer for the precise control and thorough mixing and dissolving ofinflowing materials, for example, powders which have a tendency to lumptogether. The purpose is to intermix a continuous downward flow of sucha material, or several materials, into the surface of a constantlyflowing liquid film.

In a mixer which embodies this invention, the liquid, for example,water, into which the other material is to be mixed, is admittedtangentially into an annular chamber along whose center is an invertedtruncated cone. The liquid circulates around the outer surface of thecone and rises to overflow inward and downward as a film on the innerconical surface. In the center of the inverted truncated cone is arevolving small cone spreader, powered by a central vertical shaft. Ontothe upper surface of the spreader impinges a downflowing supply ofpowder, for example, or other liquid material to be mixed. Rotation ofthe spreader swirls and centrifugally disperses this powder or othermaterial evenly in the downflowing film of liquid within the invertedcone, so that its particles are separately suspended in it, and, ifsoluble, are readily dissolved. At the base of the truncated cone, thesolution or mixture descends onto a horizontal plate rotating on thesame central shaft, and it is impelled centrifugally, through mixingpins, in a central tapering lower shell, or vessel, from which it isdischarged.

The following advantages are obtained:

1. The machine produces a continuous precisely controlled solution orsuspension at a constant rate. No supplemental mixing devices arerequired.

2. Since the material to be intermixed or dissolved is evenly dispersedinto a downflowing film, the mixing and dissolving and other chemicalreactions, if any, occur very quickly.

3. The machine aovids negative pressures which tend to cause suchconditions as adhesion of the particles to be mixed or the absorption ofdust and foreign matter.

4. Modern types of control, such as a computer punch card system and thelike, can be employed to control the actual flow, and the flow rates andproportions with high accuracy.

5. The machine is simple in construction, easy in its maintenance,relatively free from trouble and of high reliability.

A preferred embodiment of the invention will now be described, referencebeing made to the accompanying Drawing.

BRIEF DESCRIPTION OF THE DRAWING The Drawing is an elevational view,partly in section, of a preferred embodiment of the invention togetherwith a schematic presentation of a control system therefor.

DESCRIPTION OF THE PREFERRED EMBODIMENT The mixer shown in the drawingcomprises a cylindrical tank 2 for containing liquid. Its cylindricalwall is provided, at a relatively low level, with a tangential inlet 1.Within the tank 2 is a concentric inverted truncated overflow cone 3whose upper edge is above the liquid inlet 1, the inner wall of theoverflow cone 3 discharging downwardly through a central opening in thebottom of the tank 2.

Extending through the top of the tank 2 is a downwardly directed centralflow inlet 4, which may provide for the inflow of powder or othermaterial in a downward jet. Directly beneath it, at a level below theupper edge of the overflow cone 3, is a small diameter cone spreader 6,secured onto the upper end of a central vertical rotary shaft 5, whichextends downward and through the cone 3 and therebelow as will bedescribed. At a level spacedly below the bottom of the cone 3 and tank2, a mixing disc 7 is mounted onto the shaft, the disc being larger indiameter than the lower end of the cone 3, which opens onto it. Aplurality of short pins 8 are mounted on the upper surface of the disc7, arranged in circles to project upward in the space below the bottomof the tank 2. At different radial spacings, close to the spacings ofthe pins 8, are circles of similar short stationery pins 9 mounted toproject downward from the bottom of the tank 2 just above the outer edgeof the disc 7, then to substantially intermesh with the pins 8.Outwardly-of the disc 7, guide vanes I0 project downwardly from thebottom ofthe tank 2 to direct the mixture downward.

Around these elements, beneath the tank 2, is a supplementary vessel,preferably in the form of an inverted cone shell 11. It surrounds thevanes 10 and slopes downward and inward toward a central mounting forthe vertical shaft 5. Thereadjacent it is provided with an outletthrough which the mixture produced by the invention is delivered. In thelower part of the shell vessel 11 is a rotating scraper blade 12 mountedon the shaft 5 beneath the disc 7. By a conventional electric motor andbelt and sheave drive, the shaft 5 is driven from its lower end whichprojects beneath its mounting at the bottom center of the shell 11.

Liquid, for example water, supplied at a predetermined flow rate, ashereinafter described, flows into the tank inlet 1 tangentially, andcirculates about the outer surface of the inverted overflow cone 3, torise to its upper edge, which it overflowed. The overflowed liquid movesover the inner surface of the cone 3 in a spirally descending flow, topass downward through the central opening at its base. The thickness ofthe liquid film will be a function of known factors; and it will beobvious that the liquid flow rate is to be controlled to maintain thefilm-like flow of the liquid. Considering, for example, the down feedthrough the inlet 4 of powdery material which is to be dissolved inliquid admitted through the inlet 1: as such liquid descends as a filmon the inner surface of the overflow cone 3, particles of powderimpelled by rotation of the spreader cone 6 will be thereby distributedevenly over at the descending liquid film. The rotating spreader 6imparts a centrifugal force to the particles, which may already possesssubstantial energy by reason of being discharged downwardly in a jetthrough the inlet 4; and the kinetic energy of the whirling powderparticles aids in their intermixture with and dissolving into the filmof liquid. As the mixture descends onto the mixing disc 7, centrifugalforce expels it through the adjacent pins 8 and 9.

This effects a second phase of intermixture and dissolving.

The apparatus which feeds and controls the feed through the inlets l, 4will now be described. In a preferred embodiment, adapted for feeding ofpowder downwardly through a tapered bin shown uppermost in the drawings,there is provided at the base of such conventional bin a motor drivenfeeder for powder generally designated PF which leads downwardly intothe top inlet 4 which has been described. A motor driven feeder for theliquid generally designated LF includes a conventional supply tank andvalves, not otherwise described, and pumps such liquid under positivefeed control into the tangential inlet 1 of the tank 2. The supplies ofpowder and liquid are delivered in amounts precisely proportional to thespeed of motors therefor, as shown on the drawing.

Connected to the powder feeder PF and the liquid feeder LF are pulsegenerators PG and LG respectively. These generate pulse signals havingsignal rates proportionate to the amounts being fed by the feeders PF,LF. The pulse generators PG, LG are connected to a control unit U whichin turn connects to the motors of the feeders PF, LF.

On the control unit U, which may be located remote from the mixingapparatus described, are setting counters for powder PC and for liquidLC. Indicators of the flow rates D/A signalled by the powder pulsegenerator PG and the liquid pulse generator LG are also provided,designated PP and LD respectively. Also provided are integrating metersPI, Ll of the pulses as signalled for powder delivery and liquiddelivery respectively. All these controls are connected in conventionalcircuitry through comparators, to a master timer T which receives amaster pulse. The pulse generators for powder and liquid PG, LG assureproportional controlling of both feed systems from a master pulsesystem. The feed rates are readily read from the indicators PP, LD andthe total performance from the integrating meters PI, LI. Alternately,punch card or computerized controls may be added.

So accurate is the proportional control, and so even and thorough is thedistribution of material such as powder supplied through the downwardinlet 4, into the descending film of liquid on the inner surface of theoverflow cone 3, that relatively large amounts of powder may beintermixed without difficulty. There being no substantial variations inflow rates, nor negative pressures which would cause powder particles toadhere, and the powder particles being preliminarily protected from dustand moisture absorption, the mechanism defined results in such an evenintermixture in the liquid film, that, aided by the second phase ofmixing on the disc 7, relatively large amounts of powder can bedissolved into the liquid with assurance of uniformity and freedom frompowder lumps.

While the invention has been described with reference to the embodimentshown in the drawing, variations to suit particular purposes will beobvious to those skilled in the art.

I claim:

1. A continuous flow mixer comprising a tank having an outer wall formedabout a central vertical axis, a tangential inlet into said wall,

an inverted truncated overflow cone disposed in and concentric with saidtank, whereby to provide an annular space within which liquid from saidinlet is circulated, the overflow cone having an upper edge above thelevel of the tank wall inlet and having an inner conical surface and acentral outlet at the tank bottom, whereby liquid circulating in saidannular tank portion may rise to and overflow the upper edge of theoverflow cone and descend as a film over said inner conical surface,

top central inlet means to admit downwardly into I said tank along itsaxis a material ofa type capable of being dispersed into said liquid,and

means beneath said inlet and operating along said central axis todisperse and distribute such material, so admitted downwardly,centrifugally from said axis, whereby to cause its continuous and evenintermixture into such liquid film descending on the said inner conicalsurface.

2. A continuous flow mixer as defined in claim 1, wherein the means todisperse is a spreader cone mounted on a powered shaft positioned onsaid central axis.

3. A continuous flow mixer as defined in claim 1,

the means to disperse being mounted atop a vertical powered shaftextending upward along said axis from a level beneath the bottom of thetank, together with a vessel beneath said tank and surrounding a portionof the shaft at said level, and

disc-like means, mounted on said shaft within said vessel beneath theoutlet of said overflow cone, to receive and centrifugally dispel amixture descending therefrom.

4. A continuous flow mixer as defined in claim 3,

the said disc-like means having, radially outward from the outlet ofsaid overflow cone, intermeshing pin means to further intermix a mixturedischarged on said disc-like means from said overflow cone outlet.

5. A continuous flow mixer as defined in claim 1,

the means to disperse being mounted atop a vertical powered shaftextending upward along said axis from a level beneath the bottom of thetank, to

electrically powered means to feed a material to be intermixed with suchliquid downwardly to the top central inlet means,

and control means to fix precise delivery rates of said liquid feedmeans and said feed means for such material to be intermixed therewith,and their proportioned delivery.

7. A continuous flow mixer comprising:

a tank having an outer wall and an inlet into said wall;

an open top overflow vessel disposed within said tank to provide anannular space between the tank wall and the vessel, into which spaceliquid entering from said inlet can circulate, the overflow vesselhaving an upper edge, a bottom outlet and an inner surface shaped toform a descending film of liquid which has circulated in said annularspace and has risen to and overflown the upper edge of the overflowvessel, wherein the inner surface of the overflow vessel converges inthe downward direction;

material inlet means to admit into said tank and into said overflowvessel a material of a type capable of being dispersed into said liquid;and

first dispersing means adjacent said material inlet means to disperseand distribute the admitted material into the descending liquid filmalong the inner surface of the overflow vessel.

8. A continuous flow mixer as in claim 7 including a collection vesseldisposed beneath said tank and beneath said bottom outlet of theoverflow vessel to admit the mixture of material and liquid descendingalong the inner surface of the overflow vessel and exiting therefromthrough said bottom outlet thereof, and second dispersing means disposedwithin said collection vessel in the path of the exiting mixture fromthe overflow vessel for dispersing said mixture.

9. A continuous flow mixer as in claim 8 wherein said first and seconddispersing means comprise centrifugal dispersers.

10. A continuous flow mixer comprising:

a tank having an outer wall and an inlet into said wall;

an open top overflow vessel disposed within said tank to provide anannular space between the tank wall and the vessel, into which spaceliquid entering from said inlet can circulate, the overflow vesselhaving an upper edge, a bottom outlet and an inner surface shaped toform a descending film of liquid which has circulated in said annularspace and has risen to and overflown the upper edge of the overflowvessel;

a material inlet means to admit into said tank and into said overflowvessel a material of a type capable of being dispersed into said liquid;

first dispersing means adjacent said material inlet means to disperseand distribute the admitted material into the descending liquid filmalong the inner surface of the overflow vessel;

21 collection vessel disposed beneath said tank and beneath said bottomoutlet of the overflow vessel to admit the mixture of material andliquid descending along the inner surface of the overflow vessel andexiting therefrom through said bottom outlet thereof;

second dispersing means disposed within said collection vessel in thepath of the exiting mixture from the overflow vessel for dispersing saidmixture, said first and second dispersing means comprising centrifugaldispersers;

wherein said tank and overflow vessel are coaxial and wherein the innersurface of the overflow vesses converges toward said bottom outletthereof,

11. A continuous flow mixer as in claim 10 wherein the inlet into thetank wall is disposed below the level of the upper edge of the overflowvessel.

12. A continuous flow mixer as in claim 11 wherein the overflow vesselis in the shape of a truncated inverted cone.

13. A continuous flow mixer as in claim 12 wherein the first dispersingmeans comprise a spreader cone mounted on a powered shaft extendingalong the axis of the overflow vessel, and wherein said material inletmeans is positioned directly above said spreader cone.

14. A continuous flow mixer as in claim'13 wherein said seconddispersing means comprise a rotating disc disposed below the bottomoutlet of the overflow vessel and having a plurality of upwardlyextending pins.

15. A continuous flow mixer comprising:

A tank having an outlet wall and an inlet into said wall;

an open top overflow vessel disposed within said tank to provide anannular space between the tank wall and the vessel, into which spaceliquid entering from said inlet can circulate, the overflow vesselhaving an upper edge, a bottom outlet and an inner surface shaped toform a descending film of liquid which has circulated in said annularspace and has risen to and overflown the upper edge of the overflowvessel;

material inlet means to admit into said tank and into said overflowvessel a material of the type capable of being dispersed into saidliquid; and

first dispersing means adjacent said material inlet means to disperseand distribute the admitted ma terial into the descending liquid filmalong the inner surface of the overflow vessel, wherein the tank and theoverflow vessel are coaxial and the inner surface of the overflow vesselconverges in the downward direction.

16. A continuous flow mixer as in claim 15 wherein the inner surface ofthe overflow vessel is in the shape of a truncated inverted cone.

17. A continuous flow mixer as in claim 15 wherein the first dispersingmeans comprise a spreader cone mounted on a powered shaft extendingalong the com mon axis of the overflow vessel and the tank, and whereinsaid material inlet means is positioned directly above said spreadercone.

1. A continuous flow mixer comprising a tank having an outer wall formedabout a central vertical axis, a tangential inlet into said wall, aninverted truncated overflow cone disposed in and concentric with saidtank, whereby to provide an annular space within which liquid from saidinlet is circulated, the overflow cone having an upper edge above thelevel of the tank wall inlet and having an inner conical surface and acentral outlet at the tank bottom, whereby liquid circulating in saidannular tank portion may rise to and overflow the upper edge of theoverflow cone and descend as a film over said inner conical surface, topcentral inlet means to admit downwardly into said tank along its axis amaterial of a type capable of being dispersed into said liquid, andmeans beneath said inlet and operating along said central axis todisperse and distribute such material, so admitted downwardly,centrifugally from said axis, whereby to cause its continuous and evenintermixture into such liquid film descending on the said inner conicalsurface.
 2. A continuous flow mixer as defined in claim 1, wherein themeans to disperse is a spreader cone mounted on a powered shaftpositioned on said central axis.
 3. A continuous flow mixer as definedin claim 1, the means to disperse being mounted atop a vertical poweredshaft extending upward along said axis from a level beneath the bottomof the tank, together with a vessel beneath said tank and surrounding aportion of the shaft at said level, and disc-like means, mounted on saidshaft within said vessel beneath the outlet of said overflow cone, toreceive and centrifugally dispel a mixture descending therefrom.
 4. Acontinuous flow mixer as defined in claim 3, the said disc-like meanshaving, radially outward from the outlet of said overflow cone,intermeshing pin means to further intermix a mixture discharged on saiddisc-like means from said overflow cone outlet.
 5. A continuous flowmixer as defined in claim 1, the means to disperse being mounted atop avertical powered shaft extending upward along said axis from a levelbeneath the bottom of the tank, together with a vessel beneath said tankand surrounding a portion of the shaft at said level, the vessel havingthe form of an inverted cone shell and having a lower central mountingfor said shaft and having adjacent to said mounting a discharge outlet.6. A continuous flow mixer as defined in claim 1, together withelectrically powered means to feed a liquid into the tangential inlet ofthe tank, electrically powered means to feed a material to be intermixedwith such liquid downwardly to the top central inlet means, and controlmeans to fix precise delivery rates of said liquid feed means and saidfeed means for such material to be intermixed therewith, and theirproportioned delivery.
 7. A continuous flow mixer comprising: a tankhaving an outer wall and an inlet into said wall; an open top overflowvessel disposed within said tank to provide an annular space between thetank wall and the vessel, into which space liquid entering from saidinlet can circulate, the overflow vessel having an upper edge, a bottomoutlet and an inner surface shaped to form a descending film of liquidwhich has circulated in said annular space and has risen to andoverflown the upper edge of the overflow vessel, wherein the innersurface of the overflow vessel converges in the downward direction;material inlet means to admit into said tank and into said overflowvessel a material of a type capable of being dispersed into said liquid;and first dispersing means adjacent said material inlet means todisperse and distribute the admitted material into the descending liquidfilm along the inner surface of the overflow vessel.
 8. A continuousflow mixer as in claim 7 including a collection vessel disposed beneathsaid tank and beneath said bottom outlet of the overflow vessel to admitthe mixture of material and liquid descending along the inner surface ofthe overflow vessel and exiting therefrom through said bottom outletthereof, and second dispersing means disposed within said collectionvessel in the path of the exiting mixture from the overflow vessel fordispersing said mixture.
 9. A continuous flow mixer as in claim 8wherein said first and second dispersing means comprise centrifugaldispersers.
 10. A continuous flow mixer comprising: a tank having anouter wall and an inlet into said wall; an open top overflow vesseldIsposed within said tank to provide an annular space between the tankwall and the vessel, into which space liquid entering from said inletcan circulate, the overflow vessel having an upper edge, a bottom outletand an inner surface shaped to form a descending film of liquid whichhas circulated in said annular space and has risen to and overflown theupper edge of the overflow vessel; a material inlet means to admit intosaid tank and into said overflow vessel a material of a type capable ofbeing dispersed into said liquid; first dispersing means adjacent saidmaterial inlet means to disperse and distribute the admitted materialinto the descending liquid film along the inner surface of the overflowvessel; a collection vessel disposed beneath said tank and beneath saidbottom outlet of the overflow vessel to admit the mixture of materialand liquid descending along the inner surface of the overflow vessel andexiting therefrom through said bottom outlet thereof; second dispersingmeans disposed within said collection vessel in the path of the exitingmixture from the overflow vessel for dispersing said mixture, said firstand second dispersing means comprising centrifugal dispersers; whereinsaid tank and overflow vessel are coaxial and wherein the inner surfaceof the overflow vesses converges toward said bottom outlet thereof. 11.A continuous flow mixer as in claim 10 wherein the inlet into the tankwall is disposed below the level of the upper edge of the overflowvessel.
 12. A continuous flow mixer as in claim 11 wherein the overflowvessel is in the shape of a truncated inverted cone.
 13. A continuousflow mixer as in claim 12 wherein the first dispersing means comprise aspreader cone mounted on a powered shaft extending along the axis of theoverflow vessel, and wherein said material inlet means is positioneddirectly above said spreader cone.
 14. A continuous flow mixer as inclaim 13 wherein said second dispersing means comprise a rotating discdisposed below the bottom outlet of the overflow vessel and having aplurality of upwardly extending pins.
 15. A continuous flow mixercomprising: A tank having an outlet wall and an inlet into said wall; anopen top overflow vessel disposed within said tank to provide an annularspace between the tank wall and the vessel, into which space liquidentering from said inlet can circulate, the overflow vessel having anupper edge, a bottom outlet and an inner surface shaped to form adescending film of liquid which has circulated in said annular space andhas risen to and overflown the upper edge of the overflow vessel;material inlet means to admit into said tank and into said overflowvessel a material of the type capable of being dispersed into saidliquid; and first dispersing means adjacent said material inlet means todisperse and distribute the admitted material into the descending liquidfilm along the inner surface of the overflow vessel, wherein the tankand the overflow vessel are coaxial and the inner surface of theoverflow vessel converges in the downward direction.
 16. A continuousflow mixer as in claim 15 wherein the inner surface of the overflowvessel is in the shape of a truncated inverted cone.
 17. A continuousflow mixer as in claim 15 wherein the first dispersing means comprise aspreader cone mounted on a powered shaft extending along the common axisof the overflow vessel and the tank, and wherein said material inletmeans is positioned directly above said spreader cone.